Police in Greece have used tear gas to disperse striking fuel truck drivers after the government issued an emergency order to force them back to work.
The scuffles occurred as some 500 drivers gathered in protest outside the transport ministry but the incident ended quickly.
Most petrol stations around the country remained closed after a three-day strike that has hit Greece's tourism industry and led to some factory closures and fresh food shortages in parts of the country.
Fuel truck drivers oppose plans for their industry which are part of major reforms required for Greece to receive rescue loans from European countries and the International Monetary Fund (IMF).
The reforms will mean drivers will no longer be able to sell their business licenses privately, sometimes for as much as 150,000 euros (£125,000), devaluing the initial investment they make.
Facing prosecution unless they return to work, the drivers say they will not directly defy the emergency civil mobilization order but will continue their protest with various forms of disobedience.
Union leader Giorgos Tzortzatos said: "We came here to talk to the (transport) minister and look how they are treating us. We are hard-working people and we want a solution to our problems."
IMF and European auditors are in Athens to inspect the progress of the belt-tightening reforms that have already seen pensions and civil servants' salaries slashed and the welfare system tightened.
The inspection is required before Greece receives the second instalment of loans from the rescue fund worth up to 110 billion euros (£91.8 billion) from the IMF and the 15 other EU countries using the single currency.